1. Field of the Invention
The present invention relates to the art of water treatment systems. More particularly, the present invention is directed to an apparatus and method of aeration in a water filter system.
2. Description of Related Art
It is well known that water drawn from wells usually contains a variety of impurities or contaminates. The most usual contaminates occurring naturally in well water are iron, sulfur, manganese and arsenic, although many man-made contaminates are now also found. These mineral contaminates may cause stained plumbing fixtures and corroded pipes and in addition, may result in the presence of disagreeable odors and improper taste to the water.
Water with a high iron content can cause rust stains on clothing. Undesirable mineral content is removed from raw water by a variety of methods, although most of the methods involve treatment of the water with oxidizing substances. For example, removal of iron and manganese is commonly effected by running the water through a filter with a bed of minerals periodically regenerated with a chemical such as potassium permanganate to oxidize the dissolved metals forming either oxides or hydrates which are precipitated and removed in the filter. Another method that is widely used is that of injecting a quantity of oxygen, either as pure oxygen or more commonly in the form of air. Possibly the most widely accepted method for introducing air into well water is by means of air aspiration produced through use of a venturi orifice. Of a somewhat more limited use has been the injection of air under pressure into a body of water to provide the oxygen necessary to oxidize the metal ions for ultimate removal from the water.
A system illustrating the use of air aspiration to precipitate iron is shown in U.S. Pat. No. 5,096,580. In this arrangement, well water is drawn by means of a pump through a pipe and into a pressure tank. From that point, the water ultimately is directed, upon a demand basis to an oxygen induction device, which is in fact a venturi jet, that aspirates air into the water at that point. The induction of air created by the venturi orifice is located close to the filter tank so that build up of precipitated iron oxide or iron hydrates is prevented from occurring in the pipe. The preferred embodiment is shown with the oxygen induction device coupled to the valve control assembly which is coupled to the filter tank.
In U.S. Pat. No. 3,649,532, water enters through an inlet and is passed through a venturi type air aspirator unit where it then continues to flow through a valve and to an inlet tube which is located on the interior of a filter tank. An automatic air release is provided in the upper portion of the tank to vent air and sulfur containing gases to the exterior. One problem encountered with this type of system results from the fact that the incoming air/water mixture are present together for a comparatively short time before being released into the interior of the tank and oxidation of the dissolved metal content is often inadequate to effect good cleansing of the well water.
A different sort of system is shown in U.S. Pat. No. 4,749,493. In this instance, an oxygen supply is introduced into the bottom of a column which contains a plurality of rings. The interior of the column is first filled with an oxygen supply and then water flows upwardly through a tube, exiting through a screen. The water then percolates downwardly through the rings acquiring oxygen from the oxygen enriched environment that had been initially placed in the column from the oxygen supply. In this apparatus, the oxygenated water is withdrawn through the discharge ports located in the bottom portion of the column. U.S. Pat. No. 4,695,378 shows an apparatus used for the purpose of treating acid mine water and involves the use of a pair of jet pumps using a venturi effect to provide aeration of the water. Following introduction of water through aspiration, the flow is then into a static mixer which has a helical interior that swirls the water and air to provide some additional mixing of the air and water. This aspiration describes a process for introducing air into acid mine water and performing a mechanical mixing operation but does not deal with the ultimate use of water for consumer use. Other patents which may be referred to are U.S. Pat. Nos. 3,649,533, 4,659,463, 5,061,377, 5,096,596 and 5,147,530.
U.S. Pat. No. 4,534,867 discloses a system for removing iron from potable water. An air pump introduces air into the untreated water. The aerated water is then introduced into a tank containing a bed of granular activated carbon. U.S. Pat. No. 5,096,596 discloses an apparatus for removal of mineral contaminants from water comprising an aeration tank with an inlet for admitting water and an outlet for discharge. The outlet is coupled via a tube to a filter valve. The filter valve is coupled to a filter tank which receives the aerated water from the aeration tank.
While the processes that constitute the prior art recognize the use of air or oxygen introduction into water, for certain purifications, problems still exist. For example with systems utilizing venturi aspiration of air into water, the venturi devices are both difficult to maintain and to obtain the introduction of sufficient quantities of air into the water to effect complete oxidation of dissolved mineral elements. The venturi is a flow restrictor which limits water pressure to the end user or adds a load on the well pump. When oxidation does occur, depending upon the location where the air is aspirated, precipitation of mineral elements from solution can occur which can result blockage and constriction of conveying pipes. No effective system is known in which sufficient oxidation is obtained by merely tumbling air and water together. In systems using air injection, unremoved excess air creates blockages and noises in plumbing systems.
U.S. Pat. No. 5,725,759 is assigned to the instant assignee and relates to a system for removing certain contaminants or impurities from well water by oxidation effected by the injection of air into a reaction chamber having first and second sections wherein the air is first mixed intimately with incoming water through the use of baffles that break up the fluid flow paths and where thereafter in, the second section of the reaction chamber, the baffles act to strip the previously aerated water of excess air and permit it to be vented, so that it does not enter the water distribution system. The aerated water is then delivered to an iron filter via a control valve assembly.
An efficient, economical apparatus and system is provided for dissolving substantial quantities of air (oxygen) into well water and also for removing excess oxygen that might otherwise result in transport difficulties. In addition, the system insures that there is maximum physical interaction between the oxygen bearing air and the water so that thorough aeration of the water is accomplished to oxidize the maximum amount of dissolved mineral content. The apparatus further provides for continued agitation of the air/water mixture to result in the removal of excess air and to thereafter enable its venting to the exterior of the aerating reactor apparatus. Specifically, by providing a vent in an air/water reactor chamber at such a location that excess amounts of air can be present in a first section of the chamber while exhausting the excess air from a second section of the chamber.
The prior art systems are often fouled by the reaction of aeration, i.e., due to the precipitated iron. The blockage will deteriorate the system performance. Eventually, the blockage will cause failure requiring maintenance. The required maintenance can be costly, difficult and time consuming to repair.
In addition, the prior art systems have been found not to be efficient in the oxidation of iron and other impurities and the removal of the oxidized iron or other impurity.
The principal object of the present invention is to provide a method and apparatus for aeration in a water filter system which is minimizes the blockage of system components due to the precipitated iron or other impurity.
Another object of the present invention is to provide a method and apparatus for aeration in a water filter system which may be maintained and repaired quickly and in a cost effective manner.
Yet another object of the present invention is to provide a method and apparatus for aeration in a water filter system which holds the dissolved oxygen at a constant high level.
Still another object of the present invention is to provide a method and apparatus for aeration in a water filter system which may be retrofit to existing systems and provide the advantages noted herein.
The present invention therefore provides a filter for oxidizing and removing impurities from water, the filter comprising: a tank having an upper end and a lower end, an opening at the upper end, and a cavity for receiving a filter resin; an air injector coupled to the opening of the tank, the air injector having an air source inlet for coupling to a regulated air source, an air source outlet in communication with the air source inlet, the air source outlet opening into the upper end of the tank; a vent, the vent having a vent inlet and a vent outlet in communication with the vent inlet, the vent inlet opening into the upper end of the tank; an unfiltered water inlet for coupling to a source of unfiltered water, the unfiltered water inlet in fluid communication with the upper end of the tank for introducing unfiltered water into the tank; a stand pipe having an upper pipe end and a lower pipe end, the stand pipe located in the tank with the lower pipe end extending into the lower end of the tank; and a filtered water outlet in fluid communication with the upper end of the stand pipe, whereby air and unfiltered water are introduced into the upper end of the tank and the water is aerated in the tank.
In the preferred embodiment, the present invention provides an air injector adaptor having an unfiltered water inlet adapted for coupling to the unfiltered water outlet of the valve controller; an unfiltered water outlet in fluid communication with the unfiltered water inlet of the adaptor, the adaptor unfiltered water outlet adapted for coupling to the opening at the upper end of the tank; a filtered water inlet adapted for coupling to the upper end of the stand pipe; a filtered water outlet in communication with the filtered water inlet of the adaptor, the adaptor filtered water outlet adapted for coupling to the filtered water inlet of the control valve; an air source inlet adapted for coupling to a regulated air source; an air source outlet in communication with the air source inlet and adapted for opening into the upper end of the tank; and a vent , the vent having a vent inlet and a vent outlet in communication with the vent inlet, the vent inlet opening into the upper end of the tank. A float valve is provided having an upper end for sealing engagement with the vent inlet.
The present invention also provides a method of aeration in an oxidizing filter system, the method comprising the steps of: injecting air into an upper portion of an filter tank, bypassing a valve controller of the filter system; injecting unfiltered water into the head of air in the upper portion of the filter tank to aerate the unfiltered water and to replace filtered water drawn from the tank; drawing the aerated unfiltered water through a filter media so as to filter the unfiltered water; and providing the aerated filtered water on demand.